Spot Forecast
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
396
FNCA72 TJSJ 200849
FWSSJU
Spot Forecast for Bike Trail...PRFD
National Weather Service San Juan PR
449 AM AST Mon Jul 20 2026
Forecast is based on forecast start time of 0800 AST on July 20.
If conditions become unrepresentative...contact the National Weather
Service.
Please contact our office if you have questions or concerns
with this forecast at
PHONE: 787-253-4586.
.DISCUSSION...
Once again, a Fire Danger Statement (RFD) has been issued for today.
Elevated fire weather conditions are expected across the southern
coastal plains and hills of Puerto Rico. Prolonged rainfall
deficits, abnormally dry to severe drought conditions, and
critically dry fuels persist, with KBDI values remaining above
critical thresholds. In addition, a very dry air mass will
overspread the region today, with precipitable water values falling
to around 1.0 inch, promoting the driest conditions of the forecast
period.
Relative humidity values are forecast to fall into the upper 40s to
lower 50s this afternoon across the southern coastal plains of
Puerto Rico and adjacent lower elevations. Although easterly winds
are expected to be somewhat lighter than recent days as the local
pressure gradient weakens, sustained winds of 10 to 15 mph with
occasional higher gusts will continue to support elevated fire
weather conditions. Any fires that develop could spread rapidly
through dry vegetation. Fire weather conditions will continue to be
monitored closely, and a Red Flag Warning may be required if winds
become stronger than currently forecast.
.TODAY...
Sky/weather.........Sunny (0-10 percent) then becoming partly sunny
(60-70 percent). Haze in the morning. Scattered
showers in the afternoon.
Chance of pcpn......50 percent.
Max temperature.....Around 92.
Min humidity........52 percent.
Wind (20 ft)........Light winds becoming east 6 to 10 mph in the
late morning and afternoon.
Mixing height.......3600 ft AGL.
Transport winds.....East 3 to 10 mph increasing to 7 to 9 mph in
the afternoon.
Smoke dispersal.....Poor (800 knot-ft) early in the morning
increasing to fair (19900 knot-ft) in the
afternoon.
Dispersion..........4.
Eye level winds.....Light winds becoming east up to 7 mph in the
late morning and afternoon.
TIME (AST) 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........5 5 5 5 60 60 60 70 70 70
Weather cov.....DEF DEF DEF DEF SCT SCT SCT SCT SCT SCT
Weather type....HAZ HAZ HAZ HAZ RW RW RW RW RW RW
Tstm cov........
Chc of pcpn (%).0 0 0 0 40 40 40 50 50 50
Temp............85 88 89 91 91 92 92 91 90 87
RH..............58 55 54 53 53 52 52 53 55 59
20 FT wind dir..E E SE SE SE SE SE E E E
20 FT wind spd..3 6 9 12 12 12 10 9 7 6
20 FT wind gust.5 7 10 20 21 13 12 10 8 7
Eye lvl wnd dir.E E SE SE SE SE SE E E E
Eye lvl wnd spd.2 4 5 7 7 7 6 5 4 4
Eye lvl wnd gst.3 6 12 13 8 7 6 5
Mix hgt (kft)...1.2 1.9 2.7 3.4 3.6 3.5 3.3 3.0 2.6 2.0
Transp wind dir.E E E E E SE SE E E E
Transp wind spd.5 7 9 10 10 9 8 7 7 7
Dispersion......6 6 6 6 6 6 6 6 6 6
Vrate kt-ft/1K..20 20 20 20 20 20 14 14 14 14
Ventrate Cat....PR PR PR PR PR PR PR PR PR PR
.TONIGHT...
Sky/weather.........Mostly cloudy (65-75 percent) then becoming
mostly clear (20-30 percent). Scattered showers
early in the evening.
Chance of pcpn......50 percent.
Min temperature.....Around 73.
Max humidity........89 percent.
Wind (20 ft)........East winds 5 to 6 mph in the evening becoming
light.
Mixing height.......100 ft AGL.
Transport winds.....East 3 to 8 mph.
Smoke dispersal.....Fair (13700 knot-ft) early in the evening
decreasing to poor (700 knot-ft) late in the
night.
Dispersion..........4.
Eye level winds.....East winds up to 4 mph decreasing to northeast
around 3 mph overnight.
TIME (AST) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........70 70 70 30 30 30 20 20 20 20 20 20
Weather cov.....SCT SCT SCT ISO ISO ISO
Weather type....RW RW RW RW RW RW
Tstm cov........
Chc of pcpn (%).50 50 50 10 10 10 0 0 0 0 0 0
Temp............83 81 79 78 77 76 75 75 74 73 73 76
RH..............67 73 77 80 82 83 85 86 88 89 88 81
20 FT wind dir..E E E E E E E E E E NE NE
20 FT wind spd..6 7 7 7 6 6 5 5 3 3 3 3
20 FT wind gust.7 8 8 8 7 7 6 6 5 5 5 5
Eye lvl wnd dir.E E E E E E E E E E NE NE
Eye lvl wnd spd.4 4 4 4 4 4 3 3 2 2 2 2
Eye lvl wnd gst. 5 5 5 4 4 3 3 3 3
Mix hgt (kft)...1.4 0.8 0.4 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.2
Transp wind dir.E E E E NE NE NE E E E E NE
Transp wind spd.7 8 8 7 6 5 3 3 3 3 3 3
Dispersion......6 6 2 2 2 2 2 2 1 1 1 1
Vrate kt-ft/1K..14 14 1 1 1 1 1 1 1 1 1 1
Ventrate Cat....PR PR PR PR PR PR PR PR PR PR PR PR
.TUESDAY...
Sky/weather.........Sunny (5-15 percent) then becoming partly sunny
(60-70 percent). Scattered showers in the
afternoon. Isolated thunderstorms late in the
afternoon.
Chance of pcpn......50 percent.
Max temperature.....Around 93.
Min humidity........46 percent.
Wind (20 ft)........Light winds becoming south 6 to 8 mph in the
late morning and afternoon. Gusty and erratic
winds expected near thunderstorms late in the
afternoon.
Mixing height.......2600 ft AGL.
Transport winds.....Northeast 2 to 3 mph shifting to the south 2 to
6 mph in the late morning and afternoon.
Smoke dispersal.....Poor (700 knot-ft).
Dispersion..........4.
Eye level winds.....Light winds becoming south up to 5 mph in the
late morning and afternoon.
TIME (AST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........14 14 14 5 5 5 60 60 60 70 70 70
Weather cov..... SCT SCT SCT SCT SCT SCT
Weather type.... RW RW RW RW RW RW
Tstm cov........ ISO ISO ISO
Chc of pcpn (%).0 0 0 0 0 0 40 40 40 50 50 50
Temp............79 82 85 88 90 91 92 93 93 92 91 88
RH..............72 64 59 54 50 48 47 46 47 49 51 56
20 FT wind dir..NE NE NE E SE S S S S S S S
20 FT wind spd..3 2 2 3 6 8 9 9 9 8 7 6
20 FT wind gust.5 3 3 5 7 9 10 10 10 9 8 7
Eye lvl wnd dir.NE NE NE E SE S S S S S S S
Eye lvl wnd spd.2 1 1 2 4 5 5 5 5 5 4 4
Eye lvl wnd gst.3 2 2 3 6 6 6 5
Mix hgt (kft)...0.3 0.5 0.9 1.4 2.0 2.4 2.6 2.5 2.4 2.3 2.2 2.1
Transp wind dir.NE NE N NE SE S S S S S SE SE
Transp wind spd.3 2 2 2 2 2 3 3 5 5 6 6
Dispersion......1 1 4 4 4 4 4 4 6 6 6 6
Vrate kt-ft/1K..1 1 2 2 2 2 2 2 9 9 9 9
Ventrate Cat....PR PR PR PR PR PR PR PR PR PR PR PR
$$
Forecaster...C. Villanueva-Birriel
Requested by...Jose M. Martinez
Type of request...WILDFIRE
.TAG 2617461.4/SJU
.DELDT 07/20/26
.FormatterVersion 2.0.0
.EMAIL josemartin@dsp.pr.gov